pep484: attributes and related

also implements __slots__ for QueryableAttribute,
InstrumentedAttribute, Relationship.Comparator.

Change-Id: I47e823160706fc35a616f1179a06c7864089e5b5

3 files changed, 20 insertions, 3 deletions

diff --git a/lib/sqlalchemy/sql/base.py b/lib/sqlalchemy/sql/base.py
index fb959654f..248b48a25 100644
--- a/lib/sqlalchemy/sql/base.py
+++ b/lib/sqlalchemy/sql/base.py
@@ -133,6 +133,8 @@ class Immutable:
 
     """
 
+    __slots__ = ()
+
     _is_immutable = True
 
     def unique_params(self, *optionaldict, **kwargs):
@@ -145,7 +147,7 @@ class Immutable:
         return self
 
     def _copy_internals(
-        self, omit_attrs: Iterable[str] = (), **kw: Any
+        self, *, omit_attrs: Iterable[str] = (), **kw: Any
     ) -> None:
         pass
 
diff --git a/lib/sqlalchemy/sql/cache_key.py b/lib/sqlalchemy/sql/cache_key.py
index 15fbc2afb..c16fbdae1 100644
--- a/lib/sqlalchemy/sql/cache_key.py
+++ b/lib/sqlalchemy/sql/cache_key.py
@@ -36,7 +36,6 @@ if typing.TYPE_CHECKING:
     from .elements import BindParameter
     from .elements import ClauseElement
     from .visitors import _TraverseInternalsType
-    from ..engine.base import _CompiledCacheType
     from ..engine.interfaces import _CoreSingleExecuteParams
 
 
@@ -393,6 +392,13 @@ class MemoizedHasCacheKey(HasCacheKey, HasMemoized):
         return HasCacheKey._generate_cache_key(self)
 
 
+class SlotsMemoizedHasCacheKey(HasCacheKey, util.MemoizedSlots):
+    __slots__ = ()
+
+    def _memoized_method__generate_cache_key(self) -> Optional[CacheKey]:
+        return HasCacheKey._generate_cache_key(self)
+
+
 class CacheKey(NamedTuple):
     """The key used to identify a SQL statement construct in the
     SQL compilation cache.
diff --git a/lib/sqlalchemy/sql/util.py b/lib/sqlalchemy/sql/util.py
index 2e0112f08..2655adbdc 100644
--- a/lib/sqlalchemy/sql/util.py
+++ b/lib/sqlalchemy/sql/util.py
@@ -1265,7 +1265,16 @@ class ColumnAdapter(ClauseAdapter):
         if self.adapt_required and c is col:
             return None
 
-        c._allow_label_resolve = self.allow_label_resolve
+        # allow_label_resolve is consumed by one case for joined eager loading
+        # as part of its logic to prevent its own columns from being affected
+        # by .order_by().  Before full typing were applied to the ORM, this
+        # logic would set this attribute on the incoming object (which is
+        # typically a column, but we have a test for it being a non-column
+        # object) if no column were found.  While this seemed to
+        # have no negative effects, this adjustment should only occur on the
+        # new column which is assumed to be local to an adapted selectable.
+        if c is not col:
+            c._allow_label_resolve = self.allow_label_resolve
 
         return c